* We already observed a techno "Green Revolution" in our recent past. Norman Borlaug, starting in the '60s and '70s. Directly maps to wild unprecedented population growth rates and population levels. 12 years to add 1 billion mouths to feed, 4 billions in a row.

* There are fluctuations in the growth rate over time and space, but this has less impact than our intuition usually grants because we don't intuit exponential processes well. Low growth rate populations are quickly (in historical terms) taken over by high growth rates populations. It's the very logic of biology: the eternal race between exponential growth and entropic decay is won by the populations with highest growth rate * entropy resilience. We can observe it with out fail in a Petri dish. We can also observe this all over the industrialized world, with the (temporary?) exception of insular nations like Japan and South Korea. The Amish will inherit the world.

* Adapting to the industrialized world may have temporarily created the illusion that the carrying capacity is much smaller than it actually is. People started to think that they need 5000 kWh / capita / year instead of the traditional 50 kWh. In the long run, as populations bulge, people will come to terms with reality and accept, out of necessity, much lower per capita energy consumption. In socioeconomic terms, more and more people will get used to "poverty". Techno-optimist socioeconomic palliatives like UBI will, inadvertently but likely, accelerate this process.

Edit. A few words about "poverty", seen as low per capita energy requirements. There are worlds of difference between:

* 2000 BC. Running for food in the big plains / forests.

* 1000 AD. Working the fields in a medieval setting.

* 1950 AD. Living packed in small pockets of industrial high rises.

* 2200 AD (?). Living in a world-wide sprawl of high rises.

* 2700 AD (?). Living in a world-wide artificial dome, Trantor style.

Perhaps the limiting factor will turn out to be that our mammal brains break down before the nigthmare landscape that our ever more efficient techno world will eventually produce.

For 50 years the birthrate per woman is <2. This hardly is a time scale where you can say people did not realise something. I don't see the trend you are describing at all. And this is not isolated. Afaik all developed countries have this trajectory. The solution to overpopulation seems rather simple then. Just make the world developed.

https://en.wikipedia.org/wiki/List_of_countries_by_food_self...

This also doesn't square with the population growth due to immigration Germany has.